import time

scale = 50
print("执行开始".center(scale//2, '-'))
start = time.perf_counter()

for i in range(scale + 1):
    a = '*' * i
    b = '-' * (scale - i)
    c = (i / scale) * 100
    dur = time.perf_counter() - start
    print("\r{:^3.0f}%[{}->{}]{:.2f}s".format(c, a, b, dur), end='')
    time.sleep(0.1)

print("\n" + "执行结束".center(scale // 2, '-'))
